Human embryonic stem cells can be proliferated indefinitely while retaining a normal karyotype, and can be used in vitro to study the earliest stages of differentiation. While in vitro studies (drug testing, target identification) may ultimately be medically more valuable than in vivo applications, it is the latter that has captured the imagination of US government leaders. The decision to fund research on human embryonic stem cells opens up unprecedented opportunities. The public funding takes the research out of the private sector, where it has been motivated solely by economic necessities, into the public sector, where basic research can be performed without the driving force of the marketplace. The course proposed in this application, "Human Embryonic Stem Cell Culture Training Course", will provide hands-on training for investigators to learn how to culture, manipulate, and differentiate ES cells from humans in vitro. This course will bring together some of the leading experts on ES cell technology and through comparative approaches, effectively train students in the successful culture, maintenance and manipulation of ES cells. A major long-term goal for this course will be to share and improve standard protocols. Specifically, this course will cover: 1) Demonstration of proper growth conditions for cells; 2) Proper freeze-thaw cycling and preparation of cell passages; 3) Use of co-culture techniques; 4) Use of cell separation procedures; 5) Review of basic good laboratory practices for use of human biological materials; 6) Development of protocols that support the characterization of embryonic stem cells; 7) Application of standard research protocols for directed differentiation of embryonic stem cells; 8) Employment of standard detection methods for infectious organisms or other contaminants; and 9) Cross-training of techniques used in other applications of stem cell biology. These aims will be accomplished by offering intensive 10-day courses to 12 participants chosen for their outstanding research potential. The Courses will be held semi-annually at the National Human Neural Stem Cell Resource of the Neuroscience Laboratories at the Children's Hospital of Orange County Research Institute.